In the 1940ΓÇÖs haptic lenses were fitted with minimal clearance of the cornea. The lens still rested on the scleral but there was only a thin tear layer under the lens. These
lenses were called fluidless lenses
since fluid did not have to be put in
the lens prior to placement on the
eye. A hole (called an aperture or
fenestration) was put in the lens to
allow exchange.
The fluidless lenses allowed longer
wearing times since there was more
exchange of the fluid and more
oxygen reached the cornea. Lens
fitting was exacting and time consuming because of the necessity of matching the shape of the eye.
(Later modules will cover these lenses in more detail-they are still used on a limited basis for special situations or as cosmetic shells to cover damaged eyes).